Which camshaft do you use?

[PimentoTR6]

Hi Guys,

 

I have been a passive reader of nearly all the posts on this TR6 forum and have found it so so helpful on my first rebuild of a TR6, infact its my first rebuild of any car.  So i would just like to thank you all for your input and guidance:o)

 

I'm in the middle of a engine rebuild also my first and have developed a headache over which of the many Camshafts to choose.  My TR6 is a 1970 LHD which i am converting to RHD PI etc, so i need at least a 150BHP rated cam to go with my new cylinder head etc, i've just bought a standard 150bhp cam from Moss but i am now having second thoughts.  What has everybody else choosen, i'm looking for general use not race and something that wont effect the insurance too much as i'm 25 with no no claims.

 

Some i've seen are:

Fast road 83

Road 83

Ultimate road

Race rally

race

 

to name a few.

Can anyone suggest a supplier for the cams aswell?

What are the pros and cons of each?

Is the orignal 150bhp one not the one to choose?

So many questions.

 

Any advice from all you experienced guys or gals on this would really help.

[jonlar]

Hi and welcome to what I and a lot of others think is great forum and a wonderful club.   What do we call you - Pims? or what!   From my own experience, mine is a CR with Stage 3 head, lightened flywheel (revs much more freely) and a fast road cam.   Crank and everything else balanced - very smooth.   I certainly wouldn't go any hotter for road use though, you've got to make sure brakes and suspension can handle what you're wanging through the drive train safely.   Have you already got it insured?  I'm with Country Mutual (our sponsors - see banner at top of page), I declared mine as lightly tuned - no questions asked, very reasonable.

I'm sure though you'll get some other opinions expressed soon!!

[Guest ron]

Hi Pimento

I think it depends on what you want to use the car for, if you are quite happy driving about the roads in a responsible manner then the standard engine and cam are more than adequate. I would also suggest that it might be worth looking at the cylinder head before going any further with a cam if your looking for more power.

I also got the crank assembly balanced when the engine was rebuilt, but I regret not lightening the flywheel a bit as well

Ron

[PimentoTR6]

Hi,

 

My cars got the GT 6:3:1 manifold with twin exhausts and K&N filters,spin on filter, new lightened cam followers, Koni adjustable rear suspension, all round poly bushs thats as far as the mods go at the moment, i've just orderd a standard 9:5:1 head from Moss to replace my early US head.  So would putting a fast cam make that much difference?

 

What budget conscience mods would you suggest for overall performance?

 

Thanks for the help so far

Kristian

[PimentoTR6]

P.S the car is for genral road use, i was just wondering what difference a fat road cam would make and how it would feel?

 

Kris

[Guest ron]

I was always under the impression on these old long stroke BL engines the first place to start when looking for more power was the cylinder head.

Ron

[Tom Fremont]

My '250 has gotten rave reviews here in the U.S. ( where all the cars originally had carbs and 111 HP -> 104 HP ) with the early P.I. cam, gas-flowed head ( courtesy Racetorations ) with std. 9.5:1 c/r, tubular header, single-pipe exhaust and triple Webers. It's at least 1/2 second and 4 mph faster in the 1/4 mile than the published figures for TR5s.

 

In the same motor I had (2) Kent TH2 Fast Road cams fail in 25,000 miles or less, each. The second one had Kent followers and springs; the first time, not ( but it lasted twice as long as the full Kent set-up ). This was probably due to poor quality followers, so now ( per Racetorations advice ) I use competition followers and their springs. The above set-up was suggested in response to my wish for 100,000 mile life ( now at 22,000 and counting ).

 

My experience suggests the cam/follower design is somewhat failure prone relative to the rest of the engine. Hence, I would advise avoiding high-lift cams, stiff springs, and high-ratio roller rockers which subject the cam lobes to higher forces.

 

Finally, I think these (4) factors contribute to increased performance in comparable measure: 1. camshaft 2. gas-flowed head 3. tubular headers/exhaust 4. P.I. or triple Weber upgrade from twin carbs.  ::

[Guest harry dent]

If you have not ordered the head yet,may I suggest you speak to Tony of Kingston Sportscars.01359 269777.Having fitted several of his power plants and transmissions to fellow members cars I find them stunning.Max torque at 1800 rpm.

They pull like an express train.Balance,2r cam,2r head,roller rockers,high quality parts,2r metering unit,his manifold or Phoenix with single large bore exhaust.This not a mixture of parts from different suppliers which may or may not work very well but a known package and it is bloody good.I have a stage 111 head as extra and can not wate to get my TR5 back on the road.Good luck in what ever you choose to do.

Regards Harry TR5 nutter.  

[marvmul]

PimroseTR-If you can cancel your order for the new cylinder head, I would suggest to use your american spec cylinder head and have this modified to stage 3 by TriumphTune (Moss), lead free of course, and with a compression ratio of about 10. (There are other good specialists of course, but you have ordered your new cyl. head from them).The cost will be no more than a standard new head I suppose. The standard 150 hp cam will work very well with this head and your exhaust system,but of course you can ask advise on other cams. A hotter cam in a standard head will not rise the power a lot and you loose on the tractability and power in the low and mid rev range and you will almost sure be disappointed. With a stage 3 cyl. head, fuel consumption will be lower and the engine will be smooth and powerfull over a broader powerband.

As already mentioned in other replies, it's best to use the standard valve springs and I think that roller rockers are over the top for a fast road car and can create new problems.

I had my TR6 crankshaft balanced, together with flywheel, clutch and pulley, I think it helps for a smooth engine.

[john.r.davies]

All,

Of aall the UK Triumph performance specialists, Moss(TriumphTune) would be the last I would choose.  They have the heritage of Terry Hurrell. but none of the experience, as he is no longer associated with the firm and they will farm out the work.

 

UK specialists with real, current race experience include cambridge Motorsport, others mentioned above, or Jigsaw Racing.  The proprietor of the latter. Mark Field, has a long personal experience of Triumph racing, starting in Spitfires and then in TRs.   He has a solid reputation for advice and supply of performance related parts - and I'm not related to him!

 

John

[Red 6]

Hi Kris,

 

Modifying the engine really is the best bit of TR ing for me. I have rebuilt an engine which is slowly moving towards 240bhp as it settles in and i can tell you that before this engine i just did not believe how fast you can make the TR go and still be driveable on the road. Dont be fooled by BHP figures it is torque that counts and that comes from a combination of components.

 

Flow of mixture in and exhaust out should be your first port of call, therefore get a good head and whoever does it make sure they offer to blend the inlet and exhaust manifolds. If they dont offer to do this go elsewhere. I have spare heads from 2 known tr companies and they are all much of a muchness but all give noticable improvements over std.

 

Get a good exhaust manifold/system. For a non race car Phoenix is the best IMHO and i have fitted several.

 

Lighten the flywheel and it will rev off the scale, but balance all rotating components so it wont self destruct.

 

Finally the cam. Look for duration figures, 280-290 is ideal if you do everything else, and have it rolling roaded to set up the injectors or su's or webbers etc.

 

I once fitted an uprated cam without doing anything else and all that happened was that it used more fuel and didnt drive well.

 

One last point is that on this subject everyone has an opinion, talk to some one who has done it and is satisfied with the outcome.The best way is to try before you buy, but that is often impossible.

 

Good luck because if you get it right............................

[Richard Crawley]

For road use, several with experience have told me that the original 150BHP cam profile is hard to better, even with a moderate tune on the engine. So that's what I stuck with!

[Guest andythompson]

Agreed the 150bhp cam is an excellent stating point but don't get a re-manufacteured one especially from R**etorations as they are made of a cheese like material which lasts less than 1000 miles. Apparently there are a few dodgy cams in circulation so be very careful as to any "new" cams origins. I think a batch of remade blanks did not meet correct hardness specs.

 

Personally I use a Wade 444C cam which was ground on a 125bhp "three ring" cam. It has 0.265" of lift and around 286 deg duration with a 105deg lobe separation angle (as per TR5 and early 6). It was ground in Melbourne and cost 120 australian dollars. It gives 160bhp at the wheels using injection, 6-3-1 Mike the Pipe extractors and flowed head.

 

A very good cam at very good price.

[marvmul]

When you buy a Piper cam, you get a long list of warnings with it, to prevent ruining the new cam on starting up the engine : almost every one complaining about new cams that are scrap after a few hundreds of miles have to blame theirselves. I would be absolutely confident to buy a camshaft from Racetorations.

[Guest andythompson]

I don't wish to start a slanging match about any camshaft supplier but the cam was supplied (at great expense) and installed with matched Racetoration followers caps and springs. Run in 20mins at 2000 rpm, cam lube and moly-disulphide grease. Cam was scrap at 1000 miles.

 

I have built plenty of engines and this is the only one to have given any trouble. Maybe I was unlucky but I just wish to warn people that some cams are not to spec and I feel the original castings are better quality than some of the remanufactured parts.

 

Its a free country and I have found that my 50 quid reprofiled cam from Wade INFINITELY better than my 250 quid Racetorations piece of junk. Sorry for the sour post but it was a bitter experience.

[Richard Crawley]

I am lucky enough to still be running my original early 6 cam on the original "grind". It had done 80K miles, 70% of those under my ownership with regular 3000 mile or bi-annual oil changes. I had budgeted for a new cam but after detailed inspection & measurement, it was pronounced fit & well so went back into my newly rebuilt engine, as did the original "grind" crank after polishing.

This engine now runs a stage 2 “lead free” head on ballanced rotational components through a Phoenix 6: 2: 1: manifold (good manifold but a pain to fit), although this is currently feeding the standard 2 pipe set up.

[Guest Neil Russell]

My tuppence worth for what its worth is to stick with the 150BHP cam. any higher lift or longer duration cams will only work if you have enlarged valves or a fully ground and ported head. the 150 cam will give the best compromise between low down grunt and high top end. other cams designed to work higher up the rev range will make your car feel slower because you will loose a certain amount of the low end grunt the car is famous for.

 

When I mention head work I mean specific grinds removing material from the intake radius of the port, not merely cleaning up the port and matching the ports to the manifolds.

 

if you want top advice regarding TR6 engine builds then speak to Jon Wood at Classic racecraft and ask him to spec you an engine to give the characteristics you want. The cam on its own will not do it though.

 

You will probably get more by keeping to your standard componants and blueprinting them.

 

as for the other comments regarding suppliers I would just ask this simple question when phoning them:

 

"Do you do your own machining in house?"

 

stick with the engine builders and not merely the engine assemblers and you will not go far wrong. My advice is to always look at the race winners in the TR register series and ask them who assembled the engine! You will very quickly realise that there are not that many true engine builders out there.

 

My other comment is that you will only get what you pay for. if one company is offering a product at £50 and the other £250 and it appears to be the same , it generally will not be.

 

I only ever buy billet or forged cams made from new blanks??

 

Neil.

[PimentoTR6]

Does anybody have any experience of Moss cams, they said that they were made especially for them and is brand new it cost about £120 its the original P/N 607689(not written on shaft though) TR5/TR6, but it doesn't have 2 rings on the front journal just one groove, like the US spec cam, but it definately has a higer lift than my old US one.

 

Any help would be great.

 

Kris

(how do i attach an image so i can show you?)

[marvmul]

Andy, it's clear from your reply that you know what you are talking about. So I believe that the cam you got from Racetorations was junk indeed. But I think you shouldn't write off a specialist because of one bad experience. They have to rely on other companies for most of the parts they sell.

When did you buy that camshaft from Racetorations? A friend of mine installed a camshaft of this specialist, I think some six years ago but I'm not sure. The lobes where rounded very quickly and the cam material had damaged the crankshaft bearings. He didn't use cam lube and the valve springs where much to strong for the intended use.

I blamed it on the careless assembly, but perhaps Racetorations sold a batch of inferior quality cams at that time. I bought some tuning parts from them, and I have no reason to complain.

To Kris : I bought a fast road cam for my TR6 from Moss : the car has covered 45000km since witout any engine trouble .A reground or a cam made from a blank doesn't seem to make any difference by itself.

Marcel.

[Tom Fremont]

I'm running a "new" 150 BHP cam from Cambridge Motorsports. This had slightly (~1/16") wider lobes than the original and is claimed to be superior to originals. Running with their competition followers it's done 22,000 miles so far. I did observe the 2500 rpm for 20 minutes break-in protocol, along with cam lubricant, etc.

 

It's a pig of a job to replace a cam with the engine in the car - about 20 man hours - a wise choice now will reduce the likelihood of that awful prospect! ::

[Guest andythompson]

Marvmul,

 

I bought the cam about 2 years ago after much debate on which one to use and unsuccessful attempts to locate a original (ie stanpart) TR5 camshaft. I think I was probably unlucky and wish no ill of Racetorations. I have bought plenty of gear off them including mag alloys which are a great bit of kit.

However over here in Australia it is hard to work out which UK cams are good and which are bad and I honestly don't know what is available in the UK and who does the manufacture of the blanks and who does the grind... could anyone enlighten us??? Are there multiple sources of new blanks and some are inferior?

 

Due to other bad experiences encountered over here, my local Triumph specialist will only use Wade cams of Melbourne who have an excellent reputation and are very open as to the exact running in procedures and specifications of the cams.

 

I know some specialists can get very cagey about exact grind specs...

 

In my case I honestly believe the "50 quid " Wade cam is money well spent and would cost considerably more if it had UK associated taxes and labour costs.

 

Incidently the 3 ring 125bhp cam is the only common six cylinder cam that has a decent base circle to allow regrinding to a TR5 or similar profile.

[Roger H]

Pim

You may find this an interesting link to help with the decision

http://triumph.hottr6.com/tr6cams.html

There is also some other interesting stuff on his site but not necessarily in agreement with common thought.

 

Cheers

Roger

[Andy Moltu]

In the UK there are relatively few people who grind their own cams. Most of the TR specialists farm out cam grinding to the likes of Kent & Piper. Some of the profiles will be unique to that supplier and not done for the other TR specialists.

If you are in the North of the country can I suggest you give Jon Wood a call at Classic Racecraft.

[PimentoTR6]

Thanks for all the advice,

 

I think i'll go for the original 150bhp cam from Moss for the moment, seeing as my cars a US car is there anything else i NEED to change or adjust to make the new cam work perfectly?

[Richard Crawley]

I assume the head you’ve got is (or has been converted to) a CP series spec. with larger inlet valves & higher compression ratio; If it’s not too late, you may as well go for a stage 2 unleaded unit! I believe you will need to change/convert the distributor advance mechanism to CP series. It goes without saying to fit new cam followers & I’m not sure about the push rods for UK spec cars, US spec may be slightly longer – I don’t know. Go for the CP series PI linkage & inlet manifolds if you can as these are much easier to set up & maintain than the CR. If you can afford it, get a decent tubular manifold (Phoenix), it gives an instant, small but useful power increase over the standard cast unit. For maximum gain, this should really be coupled to a single pipe system but some find them a bit noisy. I am still undecided & currently run mine into a standard 2 pipe rear end. For the 130 or so quid it costs, I would get the assembled rotational unit (clutch, flywheel, crank & front pulley) dynamically balanced as it makes the unit run so smoothly. A lighter flywheel will help response but I have not bothered, I was unsure if this would aversely affect the torque the unit gives (better than sheer BHP). A spin on oil filter conversion (with or without a cooler) is a good improvement but I wouldn’t bother with an external rocker oil feed kit, they are more trouble than they are worth.